In the last 7 days I used less than 150 pounds of coal. That is all the hot water needed for a family of 6. The heat came on at night a couple times. I estimate that during the summer when the nights are at least in the 50's my usage will be 12-15 pounds a day. Based on this info coal is cheaper than propane for summer hot water.

I certainly think its worth burning over the summer, I averaged about 12# per day last year and hope to do a bit better this summer with the tweaks Ive made. I'm a bit surprised the EFM can get down that low a burn rate with the large burn pot it has, but thats great that it can. Propane is in the $3-$4 per gallon range here, so its not even an option for me. Electric heat is more economical than propane, and on par with oil in my neck of the woods, northern NJ.